Recommended hard drive temperature
in [Storage]
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From: Franc Zabkar on 16 Apr 2008 03:42 I've been reading this document which is an analysis of Google's hard disc failure rates: Failure Trends in a Large Disk Drive Population: http://research.google.com/archive/disk_failures.pdf It states that "contrary to previously reported results, we found very little correlation between failure rates and either elevated temperature or activity levels." Figure 4 "shows that failures do not increase when the average temperature increases. In fact, there is a clear trend showing that lower temperatures are associated with higher failure rates. Only at very high temperatures is there a slight reversal of this trend." "Figure 5 looks at the average temperatures for different age groups. The distributions are in sync with Figure 4 showing a mostly flat failure rate at mid-range temperatures and a modest increase at the low end of the temperature distribution. What stands out are the 3 and 4-year old drives, where the trend for higher failures with higher temperature is much more constant and also more pronounced." "Overall our experiments can confirm previously reported temperature effects only for the high end of our temperature range and especially for older drives. In the lower and middle temperature ranges, higher temperatures are not associated with higher failure rates." Figure 5 suggests that Google's optimum temperature for hard drives is between 35C and 40C. Elsewhere I found this old IBM article: http://web.archive.org/web/20000519230551/http://www.storage.ibm.com/hardsoft/diskdrdl/technolo/drivetemp/drivetemp.htm It states that "figure 2 shows the dramatic effect that temperature has on the overall reliability of a hard disk drive. Derivations [sic] from a nominal operating temperature (assumed to be maintained over the life of a drive) can result in a derivation [sic] from the nominal failure rate. As the temperature exceeds the recommended level, the failure rate increases two to three percent for every one degree rise above it. For example, a hard disk drive running for an extended period of time at five degrees above the recommended temperature can experience an increase in failure rate of 10 to 15 percent. Likewise, operating a drive below the recommended temperature can extend drive life." This last statement is a bit ambiguous. If a hard drive is more reliable at a temperature below that which is recommended, then why not recommend a lower temperature in the first place? Then again, maybe the author's intended meaning was "recommended maximum temperature". - Franc Zabkar -- Please remove one 'i' from my address when replying by email.
From: Arno Wagner on 16 Apr 2008 08:20 Previously Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: > I've been reading this document which is an analysis of Google's hard > disc failure rates: [...] If you can keep your HDDs below around 40C or so, then you will run them under data-center conditions. These conditions is what the Google study is about. An example from my personal experience is with Maxtor disks. They had direct outside airflow and stayed <30C under load and at 22C when idle. No failures in 3 years for about 50 disks. These were the same Maxtors known to die fast when run hot (e.g. at 50-60C). Conditions in a typical PC are different. The HDDs are often not directly cooled with outside air and can get hot under load. If you have temperature spikes in the 50C range or higher, temperature is a major factor in HDD death. How major exactly is currently unknown or only known to the manufacturers. Most drives have a 55C stated maximum temperature. The Maxtors I mention above had a statement in their product manual that up to 60C the drive failure rate would not increase, despite a 55C maximum temperature. There is reason to believe that statement was over-optimistic or a plain lie. So don't expect the HDD manufacturers to tell you about high-temperature life expectancy. Bottom line, the Google study shows that if you can get the drives consitently down to below 40C, temperature does not matter a lot. So the recomendation would be to have your drives (under load, on a hot day) below 40C at all times. Note that this also applies to external enclosures. Arno
From: Franc Zabkar on 16 Apr 2008 16:11 On 16 Apr 2008 12:20:06 GMT, Arno Wagner <me(a)privacy.net> put finger to keyboard and composed: >Bottom line, the Google study shows that if you can get the drives >consitently down to below 40C, temperature does not matter a lot. >So the recomendation would be to have your drives (under load, >on a hot day) below 40C at all times. Note that this also applies >to external enclosures. > >Arno AFAICS, the Google study conclusively shows that failure rates also increase when temperatures drop below 35C. In fact lower temps appear to be more dangerous than slightly higher temps, except when the drive is getting old, in which case higher temps start to become significant. - Franc Zabkar -- Please remove one 'i' from my address when replying by email.
From: Arno Wagner on 16 Apr 2008 18:10 Previously Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: > On 16 Apr 2008 12:20:06 GMT, Arno Wagner <me(a)privacy.net> put finger > to keyboard and composed: >>Bottom line, the Google study shows that if you can get the drives >>consitently down to below 40C, temperature does not matter a lot. >>So the recomendation would be to have your drives (under load, >>on a hot day) below 40C at all times. Note that this also applies >>to external enclosures. >> >>Arno > > AFAICS, the Google study conclusively shows that failure rates also > increase when temperatures drop below 35C. In fact lower temps appear > to be more dangerous than slightly higher temps, except when the drive > is getting old, in which case higher temps start to become > significant. Don't read too much into it. AFAIR they did not separate by manufacturer, model and manufactuuring date. It is quite possible that the drives running at lower temperatures were actually from a batch that had less life expectancy from the start and stay at lower temperatures because of different cooling characteristics, i.e. there may well be a systematic error in the measurements. Arno
From: Franc Zabkar on 17 Apr 2008 02:09
On 16 Apr 2008 22:10:18 GMT, Arno Wagner <me(a)privacy.net> put finger to keyboard and composed: >Previously Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: >> On 16 Apr 2008 12:20:06 GMT, Arno Wagner <me(a)privacy.net> put finger >> to keyboard and composed: > >>>Bottom line, the Google study shows that if you can get the drives >>>consitently down to below 40C, temperature does not matter a lot. >>>So the recomendation would be to have your drives (under load, >>>on a hot day) below 40C at all times. Note that this also applies >>>to external enclosures. >>> >>>Arno >> >> AFAICS, the Google study conclusively shows that failure rates also >> increase when temperatures drop below 35C. In fact lower temps appear >> to be more dangerous than slightly higher temps, except when the drive >> is getting old, in which case higher temps start to become >> significant. > >Don't read too much into it. AFAIR they did not separate by >manufacturer, model and manufactuuring date. It is quite possible that >the drives running at lower temperatures were actually from a batch >that had less life expectancy from the start and stay at lower >temperatures because of different cooling characteristics, i.e. there >may well be a systematic error in the measurements. > >Arno The way I read it, the reliability-versus-temperature result was found to be consistent across all models and manufacturers. ================================================================== Failure rates are known to be highly correlated with drive models, manufacturers and vintages. Our results do not contradict this fact. For example, Figure 2 [Annualized failure rates broken down by age groups] changes significantly when we normalize failure rates per each drive model. Most age-related results are impacted by drive vintages. However, in this paper, we do not show a breakdown of drives per manufacturer, model, or vintage due to the proprietary nature of these data. Interestingly, this does not change our conclusions. In contrast to age-related results, we note that all results shown in the rest of the paper are not affected significantly by the population mix. ================================================================== The data in this study are collected from a large number of disk drives, deployed in several types of systems across all of Google�s services. More than one hundred thousand disk drives were used for all the results presented here. The disks are a combination of serial and parallel ATA consumer-grade hard disk drives, ranging in speed from 5400 to 7200 rpm, and in size from 80 to 400 GB. All units in this study were put into production in or after 2001. The population contains several models from many of the largest disk drive manufacturers and from at least nine different models. ================================================================== - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |